The game of golf often involves the usage of a vast variety of different equipment. Generally speaking, a golfer may have several different types of clubs differing in three major categories; woods, irons, and a putter. Although different golfers may differ on what their favorite type of golf club in the bag may be, most all of them will say that their iron type golf clubs play a crucial part in their golf game.
Within the iron type category, the types of golf clubs are generally separated into two major categories, a muscle back type iron and a cavity back type iron. A muscle back type iron may generally be defined as a golf club formed from a unitary piece of metal that has a portion of increased thickness called a “muscle portion”. Muscle back type irons have been existence since the early days of golf, and U.S. Pat. No. 2,007,377 to Link is an illustration of an early design of a muscle back iron. A cavity back iron, on the other hand, may generally refer to a golf club that creates an opening near the back portion of the golf club head. Although cavity type irons may generally have an open cavity that is exposed like shown in U.S. Pat. No. 4,826,172 to Antonious, the cavity back iron may also include a closed opening construction that creates an enclosed volume as shown in U.S. Pat. No. 5,766,092 to Mimeur et al.
Although muscle back irons still remain the gold standard as the go to equipment for the better golfer, the invention of cavity back irons provides significant performance advantages compared to the traditional muscle back irons. First and foremost, by removing weight from the back portion of the golf club, cavity back irons may generally be able to increase the moment of inertia of the golf club head by placing weight near the perimeter extremities of the golf club head. In addition to increasing the moment of inertia, cavity back irons can further improve the performance of the iron type golf club head by increasing the distance of the iron type golf club head. In general, golf clubs can achieve more distance by increasing the coefficient of restitution of the striking face, which cavity back irons can achieve by thinning out the striking face.
Due to the fact that cavity back irons require an opening in the rear portion of the golf club head that can be cosmetically unappealing, golf club designers have attempted to remedy that deficiency by adding a badge to fill the cavity of the opening. U.S. Pat. No. 8,920,261 to Taylor et al. provides one illustration of an attempt at a badge that helps achieve that goal.
Focusing our discussion further on the cavity back irons, as discussed above that in order to improve the performance of these types of irons, golf club designers often try to create an extremely thin face to allow for more deflection of the face during impact with a golf ball. The increased deflection of the face during impact with a golf ball will generally allow the golf ball to travel further than a thicker face counterpart, thereby increasing the performance of the cavity back iron type golf club. U.S. Pat. No. 7,008,331 to Chen illustrates one of the earlier examples of experimenting with a thin face iron to increase the performance of an iron type golf club head.
Recognizing that thinner materials are generally less durable than thicker materials, golf club designers have attempted to counteract the durability issues associated with the thinning of the striking face portion. U.S. Pat. No. 8,961,336 to Parsons et al. provides one example of a way to address this issue by filling the internal cavity of an enclosed volume iron golf club head with a polymer to provide some structural support for the thinned face.
Despite all the attempts to improve upon the performance of an iron type golf club head, none of the designs in the current industry is capable of providing an aesthetically appealing way to address the increasing need of strength and toughness for the striking face as it gets thinner and thinner to improve the performance in a cavity type iron; especially in a cavity type iron that may or may not have a hollow cavity allowing for a filler.